U.S. patent application number 16/307315 was filed with the patent office on 2019-05-09 for bis(fluorosulfonyl) imide metal salt and method for preparing same.
This patent application is currently assigned to MORITA CHEMICAL INDUSTRIES CO., LTD.. The applicant listed for this patent is MORITA CHEMICAL INDUSTRIES CO., LTD., NIPPON SHOKUBAI CO., LTD.. Invention is credited to Yukihiro Fukata, Yasuhiro Higuchi, Naohiko Itayama, Hiromoto Katsuyama, Hiroyuki Mizuno, Yasunori Okumura, Yuichi Sato, Hirotsugu Shimizu, Kenji Yamada, Takahiro Yamauchi.
Application Number | 20190135632 16/307315 |
Document ID | / |
Family ID | 63107417 |
Filed Date | 2019-05-09 |
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United States Patent
Application |
20190135632 |
Kind Code |
A1 |
Yamada; Kenji ; et
al. |
May 9, 2019 |
BIS(FLUOROSULFONYL) IMIDE METAL SALT AND METHOD FOR PREPARING
SAME
Abstract
In the present invention, a bis (fluorosulfonyl) imide metal
salt is an alkali metal salt of bis (fluorosulfonyl) imide or an
alkaline earth metal salt of bis (fluorosulfonyl) imide. The bis
(fluorosulfonyl) imide metal salt has an average particle diameter
of not less than 0.1 mm, or has an average moisture absorption rate
of not more than 2.5 mass ppm/cm.sup.2min when sealed in a PE bag
having a thickness of 80 .mu.m and left for 30 minutes at
23.degree. C. and 65% humidity.
Inventors: |
Yamada; Kenji; (Osaka-shi,
JP) ; Shimizu; Hirotsugu; (Osaka-shi, JP) ;
Katsuyama; Hiromoto; (Suita-shi, JP) ; Mizuno;
Hiroyuki; (Suita-shi, JP) ; Okumura; Yasunori;
(Suita-shi, JP) ; Itayama; Naohiko; (Suita-shi,
JP) ; Fukata; Yukihiro; (Suita-shi, JP) ;
Sato; Yuichi; (Suita-shi, JP) ; Higuchi;
Yasuhiro; (Suita-shi, JP) ; Yamauchi; Takahiro;
(Himeji-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MORITA CHEMICAL INDUSTRIES CO., LTD.
NIPPON SHOKUBAI CO., LTD. |
Osaka-shi, Osaka
Osaka-shi, Osaka |
|
JP
JP |
|
|
Assignee: |
MORITA CHEMICAL INDUSTRIES CO.,
LTD.
Osaka-shi, Osaka
JP
NIPPON SHOKUBAI CO., LTD.
Osaka-shi, Osaka
JP
|
Family ID: |
63107417 |
Appl. No.: |
16/307315 |
Filed: |
February 2, 2018 |
PCT Filed: |
February 2, 2018 |
PCT NO: |
PCT/JP2018/003663 |
371 Date: |
December 5, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C01P 2004/20 20130101;
C01P 2006/90 20130101; H01M 8/10 20130101; C01P 2004/60 20130101;
C01P 2006/40 20130101; C01P 2004/90 20130101; C01B 21/086 20130101;
C01P 2004/32 20130101; C01P 2004/30 20130101; Y02P 70/50
20151101 |
International
Class: |
C01B 21/086 20060101
C01B021/086 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 8, 2017 |
JP |
2017-021078 |
Claims
1. A bis (fluorosulfonyl) imide metal salt which is an alkali metal
salt of bis (fluorosulfonyl) imide or an alkaline earth metal salt
of bis (fluorosulfonyl) imide, having an average particle diameter
of not less than 0.2 mm.
2. A bis (fluorosulfonyl) imide metal salt which is an alkali metal
salt of bis (fluorosulfonyl) imide or an alkaline earth metal salt
of bis (fluorosulfonyl) imide, having an average moisture
absorption rate of not more than 2.5 mass ppm/cm.sup.2min when
sealed in a PE bag having a thickness of 80 .mu.m and left for 30
minutes at 23.degree. C. and 65% humidity.
3. The bis (fluorosulfonyl) imide metal salt of claim 1, having a
shape being at least one selected from the group consisting of a
plate-like shape, a rod-like shape, a block-like shape, a
pulverized material shape, a pellet shape, a powder shape, a
granule shape, a flake shape, a sphere shape, a hemisphere shape
and a particle shape.
4. The bis (fluorosulfonyl) imide metal salt of claim 1, further
having a loose bulk specific gravity of less than 1.20.
5. A method for preparing a bis (fluorosulfonyl) imide metal salt
which is an alkali metal salt of bis (fluorosulfonyl) imide or an
alkaline earth metal salt of bis (fluorosulfonyl) imide, comprising
a shaping step of shaping said bis (fluorosulfonyl) imide metal
salt in molten state.
6. The method for preparing the bis (fluorosulfonyl) imide metal
salt of claim 5, wherein said shaping step includes a cooling step
after melting said bis (fluorosulfonyl) imide metal salt.
7. The method for preparing the bis (fluorosulfonyl) imide metal
salt of claim 6, wherein a seed crystal is used in said cooling
step.
8. The method for preparing the bis (fluorosulfonyl) imide metal
salt of claim 6, wherein a cooling temperature in said cooling step
is not more than 140.degree. C.
9. The method for preparing the bis (fluorosulfonyl) imide metal
salt of claim 5, comprising a pulverization step of pulverizing a
shaped material obtained in said shaping step.
10. The bis (fluorosulfonyl) imide metal salt of claim 2, having a
shape being at least one selected from the group consisting of a
plate-like shape, a rod-like shape, a block-like shape, a
pulverized material shape, a pellet shape, a powder shape, a
granule shape, a flake shape, a sphere shape, a hemisphere shape
and a particle shape.
11. The bis (fluorosulfonyl) imide metal salt of claim 2, further
having a loose bulk specific gravity of less than 1.20.
12. The bis (fluorosulfonyl) imide metal salt of claim 3, further
having a loose bulk specific gravity of less than 1.20.
13. The method for preparing the bis (fluorosulfonyl) imide metal
salt of claim 7, wherein a cooling temperature in said cooling step
is not more than 140.degree. C.
14. The method for preparing the bis (fluorosulfonyl) imide metal
salt of claim 6, comprising a pulverization step of pulverizing a
shaped material obtained in said shaping step.
15. The method for preparing the bis (fluorosulfonyl) imide metal
salt of claim 7, comprising a pulverization step of pulverizing a
shaped material obtained in said shaping step.
16. The method for preparing the bis (fluorosulfonyl) imide metal
salt of claim 8, comprising a pulverization step of pulverizing a
shaped material obtained in said shaping step.
Description
FIELD
[0001] The present invention relates to a bis (fluorosulfonyl)
imide metal salt and a method for preparing the same.
BACKGROUND
[0002] The salts of fluorosulfonyl imide and their derivatives are
useful as intermediates of compounds having N (SO.sub.2F) groups or
N (SO.sub.2F).sub.2 groups. Also, they are useful compounds in a
variety of applications such as electrolytes, additives to
electrolyte liquids of fuel cells, selective electrophilic
fluorinating agents, photo acid generators, thermal acid
generators, and near-infrared absorbing dyes.
[0003] Generally, salts of fluorosulfonylimide have high
hygroscopicity, and when they are made into fine powder, they tends
to easily absorb moisture and easily scatter. Therefore, it caused
problems of handling difficulties.
[0004] Patent Literature 1 describes a method for preparing
granules or powder of disulfonylamide alkali metal salt having a
mode diameter not more than 80 .mu.m. However, in the method for
preparing the disulfonylamide alkali metal salt using solvents, the
residual solvents caused problems when the particle diameter is
increased.
[0005] Patent Literature 2 discloses that a yield of not less than
99% of lithium salt of bis (fluorosulfonyl) imide is obtained by
reacting an equimolar amount of bis (fluorosulfonyl) imide and
lithium fluoride at 180.degree. C. for 1 hour in an autoclave with
solvents of hydrogen fluoride. However, methods for molding the
obtained lithium salts are not described.
CITATION LIST
Patent Literature
[0006] [Patent Literature 1] WO 2015/072353
[0007] [Patent Literature 2] CA 2527802
SUMMARY
Technical Problem
[0008] Accordingly, the object of the present invention is to
provide bis (fluorosulfonyl) imide metal salt which can hardly
absorb moisture, can hardly be scattered, and then, can be easily
handled. Additionally, the other object of the present invention is
to provide methods for preparing the bis (fluorosulfonyl) imide
metal salt.
Solution to Problem
[0009] The inventors have intensively studied in order to solve the
above-mentioned problems. And as a result, they found that, by
subjecting a bis (fluorosulfonyl) imide metal salt to a shaping
step in molten state, the bis (fluorosulfonyl) imide metal salt
which can hardly absorb moisture, can hardly be scattered, and
then, can be easily handled, and which has little residual solvents
and impurities can be provided. They also found a method for
preparing the bis (fluorosulfonyl) imide salt can be provided. Then
finally, they have completed the present invention.
[0010] In the present invention, a bis (fluorosulfonyl) imide metal
salt, which is an alkali metal salt of bis (fluorosulfonyl) imide
or an alkaline earth metal salt of bis (fluorosulfonyl) imide, has
an average particle diameter of not less than 0.1 mm.
[0011] Further, a bis (fluorosulfonyl) imide metal salt, which is
an alkali metal salt of bis (fluorosulfonyl) imide or an alkaline
earth metal salt of bis (fluorosulfonyl) imide, has an average
moisture absorption rate of not more than 2.5 mass ppm/cm.sup.2min
when sealed in a PE bag having a thickness of 80 .mu.m and left for
30 minutes at 23.degree. C. and 65% humidity.
[0012] Preferably, the bis (fluorosulfonyl) imide metal salt has a
shape being at least one selected from the group consisting of a
plate-like shape, a rod-like shape, a block-like shape, a
pulverized material shape, a pellet shape, a powder shape, a
granule shape, a flake shape, a sphere shape, a hemisphere shape
and a particle shape.
[0013] Preferably, the bis (fluorosulfonyl) imide metal salt
further has a loose bulk specific gravity of less than 1.20.
[0014] Further, a method for preparing a bis (fluorosulfonyl) imide
metal salt which is an alkali metal salt of bis (fluorosulfonyl)
imide or an alkaline earth metal salt of bis (fluorosulfonyl)
imide, comprises a shaping step of shaping the bis (fluorosulfonyl)
imide metal salt in molten state.
[0015] Preferably, the shaping step includes a cooling step after
melting the bis (fluorosulfonyl) imide metal salt.
[0016] Preferably, a seed crystal is used in the cooling step.
[0017] Preferably, a cooling temperature in the cooling step is not
more than 140.degree. C.
[0018] Preferably, the method for preparing the bis
(fluorosulfonyl) imide metal salt comprises a pulverization step of
pulverizing a shaped material obtained in the shaping step.
Advantageous Effects of Invention
[0019] According to the bis (fluorosulfonyl) imide metal salt and
the method for preparing the same of the present invention, the bis
(fluorosulfonyl) imide metal salt which can hardly absorb moisture,
can hardly be scattered, and then, can be easily handled, and the
method for preparing the bis (fluorosulfonyl) imide metal salt can
be provided.
DESCRIPTION OF EMBODIMENTS
1. Bis (fluorosulfonyl) imide Metal Salt
[0020] In the bis (fluorosulfonyl) imide metal salt of the present
invention, the bis (fluorosulfonyl) imide metal salt is the alkali
metal salt of bis (fluorosulfonyl) imide or the alkaline earth
metal salt of bis (fluorosulfonyl) imide, and has an average
particle diameter of not less than 0.1 mm. The average particle
diameter is preferably not less than 0.2 mm, more preferably not
less than 0.5 mm, further preferably not less than 1 mm, and
particularly preferably not less than 3 mm. An upper limit is not
particularly limited, for example, it is preferably not more than
50 mm, more preferably not more than 20 mm, and further preferably
not more than 10 mm. When the average particle diameter is made as
described above, the salt can hardly absorb moisture, can hardly be
scattered, and then, can be easily handled. On the other hand, when
it is more than the upper limit, the salt can hardly be handled and
its dissolution rate into electrolyte solvents becomes low.
[0021] The bis (fluorosulfonyl) imide metal salt of the present
invention may be a composition containing solvents, unreacted
substances, or the like which are included upon the salt preparing.
A content of the bis (fluorosulfonyl) imide metal salt in the
composition is preferably not less than 98 mass %, more preferably
not less than 99 mass %, further preferably not less than 99.5 mass
%. In the bis (fluorosulfonyl) imide metal salt of the present
invention, it is preferable that an amount of the residual solvents
are small. A content of the solvents is preferably not more than 70
mass ppm, more preferably not more than 50 mass ppm, further
preferably not more than 30 mass ppm, particularly preferably not
more than 10 mass ppm, more particularly preferably not more than 1
mass ppm, and most preferably no solvent (under a detection
limit).
[0022] As the solvents, for example, an organic solvent can be
used. A boiling point of the solvents are, for example, 0 to
250.degree. C. Specifically, examples of the solvents include
aprotic solvents. Examples of the aprotic solvents include
aliphatic ether solvents such as dimethoxymethane, 1,
2-dimethoxyethane, tetrahydrofuran, 2- methyltetrahydrofuran, 1,
3-dioxane, 4-methyl-1, 3-dioxolane, cyclopentylmethyl ether,
methyl-t-butyl ether, diethylene glycol dimethyl ether, diethylene
glycol diethyl ether and triethylene glycol dimethyl ether; ester
solvents such as methyl formate, methyl acetate, ethyl acetate,
isopropyl acetate, butyl acetate and methyl propionate; amide
solvents such as N, N-dimethylformamide and N-methyl oxazolidinone;
nitro solvents such as nitromethane and nitrobenzene; sulfur-based
solvents such as sulfolane, 3-methyl sulfolane and dimethyl
sulfoxide; nitrile solvents such as acetonitrile, propionitrile,
isobutyronitrile, butyronitrile, valeronitrile and benzonitrile.
Also, examples of the solvents include poor solvents for the
fluorosulfonylimide alkali metal salt such as aromatic hydrocarbon
solvents; linear, branched or cyclic aliphatic hydrocarbon
solvents; and aromatic ether solvents.
[0023] Examples of the poor solvents include aromatic hydrocarbon
solvents such as toluene (boiling point 110.6.degree. C.), o-xylene
(boiling point 144.degree. C.), m-xylene (boiling point 139.degree.
C.), p-xylene (boiling point 138.degree. C.), ethylbenzene (boiling
point 136.degree. C.), isopropylbenzene (boiling point 153.degree.
C.), 1,2,3-trimethylbenzene (boiling point 169.degree. C.),
1,2,4-trimethylbenzene (boiling point 168.degree. C.),
1,3,5-trimethylbenzene (boiling point 165.degree. C.), tetralin
(boiling point 208.degree. C.), cymene (boiling point 177.degree.
C.), methylethylbenzene (boiling point 153.degree. C.) and
2-ethyltoluene (boiling point 164.degree. C.); linear or branched
aliphatic hydrocarbon solvents such as octane (boiling point
127.degree. C.), decane (boiling point 174.degree. C.), dodecane
(boiling point 217.degree. C.), undecane (boiling point 196.degree.
C.), tridecane (boiling point 234.degree. C.), decalin (boiling
point 191.degree. C.), 2,2,4,6,6-pentamethylheptane (boiling point
170.degree. C.-195.degree. C.), isoparaffin [e.g., "MARUKASOL R" (a
mixture of 2,2,4,6,6-pentamethylheptane and
2,2,4,4,6-pentamethylheptane manufactured by Maruzen Petrochemical
Co., LTD., boiling point 178.degree. C.-181.degree. C.), "Isopar
(registered trademark) G" (C 9 -C 11 mixed isoparaffin manufactured
by Exxon Mobil Corporation, boiling point 167.degree.
C.-176.degree. C.) and "Isopar (registered trademark) E" (C 8 -C 10
mixed isoparaffin manufactured by Exxon Mobil Corporation, boiling
point 115.degree. C.-140.degree. C.)]; cyclic aliphatic hydrocarbon
solvents such as cyclohexane (boiling point 81.degree. C.),
methylcyclohexane (boiling point 101.degree. C.),
1,2-dimethylcyclohexane (boiling point 123.degree. C.),
1,3-dimethylcyclohexane (boiling point 120.degree. C.),
1,4-dimethylcyclohexane (boiling point 119.degree. C.),
ethylcyclohexane (boiling point 130.degree. C.),
1,2,4-trimethylcyclohexane (boiling point 145.degree. C.),
1,3,5-trimethylcyclohexane (boiling point 140.degree. C.),
propylcyclohexane (boiling point 155.degree. C.), butylcyclohexane
(boiling point 178.degree. C.) and alkylcyclohexane having 8 to 12
carbon atoms [e.g., "SWACLEAN 150" (mixture of C9 alkylcyclohexane
manufactured by Maruzen Petrochemical Co., LTD, boiling point
152.degree. C.-170.degree. C.)]; aromatic ether solvents such as
anisole (boiling point 154.degree. C.), 2-methylanisole (boiling
point 170.degree. C.), 3-methylanisole (boiling point 175.degree.
C.) and 4-methylanisole (boiling point 174.degree. C.); and the
like.
[0024] However, the solvents defined by the present invention is
not particularly limited to the above specific examples.
Determination of Average Particle Diameter
[0025] In the present specification, an average particle diameter
means a 50% mass average particle diameter based on JIS Z 8801-1.
Specifically, as the bis (fluorosulfonyl) imide metal salt, for
example, 50 g of formed bodies of LiFSI [lithium bis
(fluorosulfonyl) imide] is put into a standard JIS sieve, and the
sieve is covered with an upper lid and a bottom lid. The formed
bodies may be the shaped materials described later. After shaking
the sieve up and down 300 times, a particle diameter distribution
is measured and the 50% average particle diameter is calculated.
When there are particles bigger than the mesh size not defined in
JIS Z 8801, the 50% average particle diameter can be defined by
actually measuring with a calliper and setting a minimum length as
the particle diameter instead. When the particle has a
hemispherical shape, its diameter can be regarded as the minimum
length.
Loose Bulk Specific Gravity
[0026] The bis (fluorosulfonyl) imide metal salt of the present
invention preferably has a loose bulk specific gravity of less than
1.20. When the salt has the loose bulk specific gravity of in
described above value, the salt can hardly absorb moisture, can
hardly be scattered, and then, can be easily handled. The loose
bulk specific gravity is more preferably less than 1.15. The lower
limit of the loose bulk specific gravity is not particularly
limited, but may be about 0.50, for example.
[0027] The loose bulk specific gravity (d) can be obtained by the
following formula according to the Japan Powder Industry Technology
Association standard SAP 05-98.
d=x/y(g/cm.sup.3)
In the above formula, y cm.sup.3 is a volume of x g of sample when
the x g of sample is naturally fell into a 100 cm.sup.3 measuring
cylinder from a funnel with a height of 10 cm.
[0028] In the bis (fluorosulfonyl) imide metal salt of the present
invention, the bis (fluorosulfonyl) imide metal salt is the alkali
metal salt of bis (fluorosulfonyl) imide or the alkaline earth
metal salt of bis (fluorosulfonyl) imide, and has the average
moisture absorption rate of not more than 2.5 mass ppm/cm.sup.2min
when sealed in a PE bag having a thickness of 80 .mu.m and left for
30 minutes at 23.degree. C. and 65% humidity. The original water
content of the bis (fluorosulfonyl) imide metal salt for measuring
the moisture absorption rate at 23.degree. C. and 65% humidity is 1
to 1000 mass ppm, preferably 1 to 500 mass ppm, more preferably 1
to 100 mass ppm, further preferably 1 to 60 ppm by mass.
[0029] The moisture absorption rate is preferably not more than 2.0
mass ppm/cm.sup.2min, more preferably not more than 1.5 mass
ppm/cm.sup.2min, further preferably not more than 1.0 mass
ppm/cm.sup.2min. A lower limit is preferably 0 mass
ppm/cm.sup.2min. When the moisture absorption rate is set as
above-described range, the salt can hardly absorb moisture, can
hardly be scattered, and then, can be easily handled.
2. Shaped Material of Bis (fluorosulfonyl) imide Metal Salt
[0030] The shaped material of the bis (fluorosulfonyl) imide metal
salt of the present invention preferably has a shape being at least
one selected from the group consisting of a plate-like shape, a
rod-like shape, a block-like shape, a pulverized material shape, a
pellet shape, a powder shape, a granule shape, a flake shape, a
sphere shape, a hemisphere shape and a particle shape.
3. Method for Preparing Bis (fluorosulfonyl) imide Metal Salt
[0031] In the present invention, the method for preparing the bis
(fluorosulfonyl) imide metal salt, which is the alkali metal salt
of bis (fluorosulfonyl) imide or the alkaline earth metal salt of
bis (fluorosulfonyl) imide, comprises the shaping step of shaping
the bis (fluorosulfonyl) imide metal salt in molten state.
[0032] In the method for preparing the bis (fluorosulfonyl) imide
metal salt of the present invention, a temperature of the bis
(fluorosulfonyl) imide metal salt in the molten state is preferably
not less than 80.degree. C.
[0033] In the method for preparing the bis (fluorosulfonyl) imide
metal salt of the present invention, the shaping step preferably
includes a cooling step after melting the bis (fluorosulfonyl)
imide metal salt.
[0034] Further, in the method for preparing the bis
(fluorosulfonyl) imide metal salt of the present invention, a
cooling temperature in the cooling step is preferably not less than
40.degree. C. and not more than 140.degree. C.
[0035] In the method for preparing the bis (fluorosulfonyl) imide
metal salt of the present invention, the bis (fluorosulfonyl) imide
metal salt is preferably prepared by reacting a mixture containing
bis (fluorosulfonyl) imide and an alkali metal compound or an
alkaline earth metal compound (hereinafter simply referred to as a
metal compound in the present specification). Further, after the
reaction, a ratio of total mass of the bis (fluorosulfonyl) imide,
the metal compound, and the bis (fluorosulfonyl) imide metal salt
to mass of an entire reacted mixture is more preferable not less
than 0.8.
[0036] In the present invention, methods for preparing the bis
(fluorosulfonyl) imide is not particularly limited. For example,
the method for preparing the bis (fluorosulfonyl) imide from a bis
(sulfonyl halide) imide by using a fluorinating agent can be used.
In the bis (sulfonyl halide) imide, Cl, Br, I and At other than F
are exemplified as a halogen.
[0037] A fluorination step of preparing the bis (fluorosulfonyl)
imide by using the fluorinating agent from the bis (sulfonyl
halide) imide will be described below.
Fluorination Step
[0038] In the fluorination step, the fluorination reaction of the
bis (sulfonyl halide) imide is carried out. For example, a method
described in CA2527802, and a method described in Jean'ne M.
Shreeve et al., Inorg. Chem. 1998, 37 (24), 6295-6303 can be used.
The bis (sulfonyl halide) imide as a starting raw material may be a
commercially available one. It can also be a compound prepared by
known methods. In addition, a method, described in JP 1996-511274
A, for preparing the bis (fluorosulfonyl) imide by using urea and
fluorosulfonic acid can be used.
[0039] As the method for preparing the bis (fluorosulfonyl) imide
by using the fluorinating agent from the bis (sulfonyl halide)
imide, the method for using hydrogen fluoride as the fluorinating
agent can be preferably used. As an example, a fluorination
reaction of bis (chlorosulfonyl) imide is represented by formula
(1) indicated below. For example, the bis (fluorosulfonyl) imide
can be obtained by introducing the hydrogen fluoride into the bis
(chlorosulfonyl) imide.
##STR00001##
[0040] A molar ratio of the hydrogen fluoride to the bis (sulfonyl
halide) imide at the starting point of the fluorination step is
preferably not less than 2.0. As a lower limit, not less than 2.1
or not less than 2.2 can be exemplified. As an upper limit, not
more than 10, not more than 5, not more than 3.0 or not more than
2.5 can be exemplified. By setting the molar ratio in this manner,
the fluorination of the bis (sulfonyl halide) imide can be carried
out more surely. In case of a small amount of use, it is not
preferable because the reaction rate is lowered, and because the
reaction is not sufficiently carried out. In case of a large amount
of use, it is not preferable because the recovery of raw materials
becomes complicated and the productivity may decrease.
[0041] The fluorination step is performed at a temperature not less
than 20.degree. C., not less than 40.degree. C., not less than
60.degree. C. or not less than 80.degree. C. as a lower limit. As
an upper limit of the temperature, not more than 200.degree. C.,
not more than 160.degree. C., not more than 140.degree. C. or not
more than 120.degree. C. can be mentioned.
[0042] The temperature can be selected appropriately by examining
the reaction rate. The fluorination step can be carried out under
either high pressure or normal pressure.
Metal Salt Production Step
[0043] In a metal salt production step, the bis (fluorosulfonyl)
imide metal salt is produced by reacting a mixture containing the
bis (fluorosulfonyl) imide obtained by the above-mentioned methods
and the metal compound. In methods of charging the bis
(fluorosulfonyl) imide and the metal compound, the reaction may be
started after charging each material initially, or the reaction may
be started while each material is continuously charged. When
charging continuously, each material may be charged separately, or
slurry of the materials may be prepared in advance and put the
slurry in.
[0044] The reacted mixture is obtained by reacting the mixture
containing the bis (fluorosulfonyl) imide and the metal compound.
The reacted mixture includes the unreacted bis (fluorosulfonyl)
imide, the unreacted metal compound, and the bis (fluorosulfonyl)
imide metal salt. After the reaction, a total of mass ratios of the
bis (fluorosulfonyl) imide, the metal compound and the bis
(fluorosulfonyl) imide metal salt to the entire reacted mixture is
not less than 0.8, preferably not less than 0.85, more preferably
not less than 0.9, further preferably not less than 0.95. After the
reaction, when the total of mass ratios of the bis (fluorosulfonyl)
imide, the metal compound and the bis (fluorosulfonyl) imide metal
salt to the entire reacted mixture is in such a range, the reaction
is easily handled because a reaction vessel such as an autoclave is
not needed.
[0045] In the mixture containing the bis (fluorosulfonyl) imide and
the metal compound at the beginning of the reaction, a total of
mass ratios of the bis (fluorosulfonyl) imide and the metal
compound to the entire mixture containing bis (fluorosulfonyl)
imide and the metal compound is preferably not less than 0.8, more
preferably not less than 0.85, further preferably not less than
0.9, particularly preferably not less than 0.95. At the beginning
of the reaction, when the total of mass ratios of the bis
(fluorosulfonyl) imide and the metal compound to the entire mixture
containing bis (fluorosulfonyl) imide and the metal compound is in
such a range, the reaction is easily handled because a reaction
vessel such as an autoclave is not needed.
[0046] As the metal compound, alkali metals are preferable.
[0047] As the alkali metals, Li, Na, K, Rb, Cs or the like can be
exemplified, and Li is preferable. As alkaline earth metals, Mg,
Ca, Sr and Ba can be exemplified.
[0048] Examples of the alkali metal compound include hydroxides
such as LiOH, NaOH, KOH, RbOH and CsOH; carbonates such as
Li.sub.2CO.sub.3, Na.sub.2CO.sub.3, K.sub.2CO.sub.3,
Rb.sub.2CO.sub.3 and Cs.sub.2CO.sub.3; hydrogencarbonates such as
LiHCO.sub.3, NaHCO.sub.3, KHCO.sub.3, RbHCO.sub.3 and CsHCO.sub.3;
chlorides such as LiCl, NaCl, KCl, RbCl, CsCl; fluorides such as
LiF, NaF, KF, RbF and CsF; alkoxide compounds such as CH.sub.3OLi
and EtOLi; alkyl-lithium compounds such as EtLi, BuLi and t-BuLi
(Et represents an ethyl group, Bu represents a butyl group); or the
like. Examples of the alkaline earth metal compound include
hydroxides such as Mg(OH).sub.2, Ca(OH).sub.2, Sr(OH).sub.2 and
Ba(OH).sub.2; carbonates such as MgCO.sub.3, CaCO.sub.3, SrCO.sub.3
and BaCO.sub.3; chlorides such as MgCl.sub.2, CaCl.sub.2,
SrCl.sub.2 and BaCl.sub.2; fluorides such as MgF.sub.2, CaF.sub.2,
SrF.sub.2 and BaF.sub.2; or the like.
[0049] In the method for preparing the bis (fluorosulfonyl) imide
metal salt of the present invention, it is preferable that the
metal compound is the alkali metal halide as the alkali metal
compound, and that the method includes a step of removing hydrogen
halides formed during the reaction. Further, it is preferable that
the alkali metal compound is lithium fluoride, and that the method
includes a step of removing a hydrogen fluoride formed during the
reaction.
[0050] As the alkali metals, among these, alkali metal halides such
as LiF, NaF, KF, LiCl, NaCl and KCl are preferable, and LiF is
particularly preferable.
[0051] As an example, preparation of bis (fluorosulfonyl) imide
lithium salt [lithium bis (fluorosulfonyl) imide] by reacting a
mixture containing bis (fluorosulfonyl) imide and LiF is
represented by formula (2) indicated below.
##STR00002##
[0052] There is a possibility that the reacted mixture obtained
after the reaction of the mixture containing the bis
(fluorosulfonyl) imide and LiF includes unreacted bis
(fluorosulfonyl) imide and unreacted LiF. The reacted mixture at
least includes lithium salt of bis (fluorosulfonyl) imide and
by-produced HF. The reacted mixture obtained after the reaction
preferably includes FSO.sub.2NH.sub.2 and/or LiFSO.sub.3.
[0053] After the reaction, a total of mass ratios of the bis
(fluorosulfonyl) imide, LiF and the lithium salt of the bis
(fluorosulfonyl) imide to an entire reacted mixture is preferably
not less than 0.8, more preferably not less than 0.85, further
preferably not less than 0.9, particularly preferably not less than
0.95. After the reaction, when the total of mass ratios of the bis
(fluorosulfonyl) imide, LiF and the lithium salt of bis
(fluorosulfonyl) imide to the entire reacted mixture is in such a
range, a reaction vessel such as an autoclave is not needed, and a
removal of hydrogen fluoride after the reaction becomes easy.
Therefore, preferably, it is possible to provide the method for
producing the bis (fluorosulfonyl) imide alkali metal salt, which
can reduce the amount of hydrogen fluoride having high corrosivity
and can easily remove hydrogen fluoride from the product. It is
also preferable that a step of removing hydrogen fluoride formed
during the reaction is included.
[0054] A total of mass ratios of the mixture containing bis
(fluorosulfonyl) imide and LiF to the entire mixture containing the
bis (fluorosulfonyl) imide and LiF at the beginning of the reaction
is preferably not less than 0.8, more preferably not less than
0.85, further preferably not less than 0.9, particularly preferably
not less than 0.95. When the total of mass ratios to the entire
mixture containing the bis (fluorosulfonyl) imide and LiF at the
beginning of the reaction is in such a range, a reaction vessel
such as an autoclave is not needed and the removal of hydrogen
fluoride after the reaction becomes easier.
[0055] In the metal salt production step, hydrogen fluoride can be
used in such a range that the total of mass ratios of the bis
(fluorosulfonyl) imide, the metal compound and the bis
(fluorosulfonyl) imide metal salt to the entire mixture after the
reaction is not less than 0.8. In the metal salt production step,
hydrogen fluoride may not be used.
[0056] Also, in the method for preparing the bis (fluorosulfonyl)
imide metal salt by the reaction of the mixture containing the bis
(fluorosulfonyl) imide and the alkali metal compound or the
alkaline earth metal compound of the present invention, when the
metal compound is lithium fluoride, it is preferable that a step of
proceeding the mixture while removing the hydrogen fluoride at a
pressure of not higher than 1013 hPa is included. The proceeding
includes reaction, aging, and/or devolatilization.
[0057] In the method for preparing the bis (fluorosulfonyl) imide
metal salt of the present invention, the total of mass ratios of
the bis (fluorosulfonyl) imide and the alkali metal compound or the
alkaline earth metal compound to the entire mixture containing bis
(fluorosulfonyl) imide and the metal compound at the beginning of
the reaction is preferably not less than 0.8. The metal salt
preparing reaction is carried out with a small amount of solvent or
preferably without solvent. When the metal compound is lithium
fluoride, in order to promote the lithiation reaction, it is
effective to remove HF (hydrogen fluoride) generated as a
by-product from the system. The increase in the purity of LiFSI
[bis (fluorosulfonyl) imide lithium salt] is limited, even if the
mixture is aged at normal pressure at near the end of the reaction.
The purity of LiFSI is effectively improved by removing HF under
reduced pressure.
[0058] In the method for preparing the bis (fluorosulfonyl) imide
metal salt of the present invention, the bis (fluorosulfonyl) imide
metal salt having small residual solvents are obtained.
[0059] A reaction temperature of the mixture containing the bis
(fluorosulfonyl) imide and the metal compound is not less than
50.degree. C., preferably not less than 80.degree. C., more
preferably not less than 100.degree. C., further preferably not
less than 120.degree. C. An upper limit of the temperature is not
more than 180.degree. C., or not more than 160.degree. C. The
reaction can be performed even at 140.degree. C., or 150.degree. C.
If the reaction temperature is too low, undesirably, the reaction
may not proceed sufficiently. If the reaction temperature is too
high, undesirably, the product may decompose. The reaction may
start at normal temperature, and then, the reaction temperature may
increase gradually. Also, the reaction may start under heated
condition. In order to proceed the reaction sufficiently, it is
preferably near the melting point of the bis (fluorosulfonyl) imide
metal salt at the end of the reaction. In the case of lithium bis
(fluorosulfonyl) imide, since the melting point is 143.degree. C.,
the temperature at the end of preparing metal salt is preferably
not less than 130.degree. C., more preferably not less than
140.degree. C. It is preferably not more than 170.degree. C., more
preferably not more than 160.degree. C.
[0060] A pressure range of the reaction is preferably not higher
than 1250 hPa, more preferably not higher than 1150 hPa, further
preferably not higher than 1050 hPa. An inert gas such as nitrogen
may or may not be introduced into the solution for the purpose of
promoting the reaction.
[0061] A molar ratio of the alkali metal or the alkaline earth
metal included in the metal compound to bis (fluorosulfonyl) imide
is preferably not less than 0.80 and not more than 1.20, more
preferably not less than 0.90 and not more than 1.10, further
preferably not less than 0.95 and not more than 1.05, most
preferably around 1.00. When an amount of bis (fluorosulfonyl)
imide is excessive, the excess bis (fluorosulfonyl) imide can be
removed by devolatilization. When the alkali metal or the alkaline
earth metal included in the metal compound is excessive, the excess
alkali metal or the alkaline earth metal can be removed from the
obtained bis (fluorosulfonyl) imide metal salt composition by
filtering the obtained bis (fluorosulfonyl) imide metal salt
composition in molten state or after dissolving in electrolyte
solvents.
[0062] In the metal salt production step, the bis (fluorosulfonyl)
imide metal salt is obtained in molten state. A temperature of the
bis (fluorosulfonyl) imide metal salt in molten state is preferably
not less than 80.degree. C., more preferably not less than
100.degree. C., further preferably not less than 140.degree. C. An
upper limit is preferably not more than 180.degree. C., more
preferably not more than 160.degree. C., further preferably not
more than 150.degree. C.
[0063] The mixture containing the bis (fluorosulfonyl) imide and
the alkali metal compound or the alkaline earth metal compound may
be aged after the reaction. An aging temperature is not less than
50.degree. C., preferably not less than 80.degree. C., more
preferably not less than 100.degree. C., further preferably not
less than 120.degree. C. An upper limit of the temperature is not
more than 180.degree. C., or not more than 160.degree. C. The aging
can be performed even at 140.degree. C., or 150.degree. C. If the
aging temperature is too low, undesirably, the aging may not
proceed sufficiently. If the aging temperature is too high,
undesirably, the product may be decomposed. In the present
invention, when the alkali metal compound is lithium fluoride, the
aging preferably proceeds while removing hydrogen fluoride at a
pressure of not higher than 1013 hPa. The removal of the hydrogen
fluoride may proceed by introducing gases into the system. Examples
of the usable gases include inert gases such as nitrogen and argon,
and dry air.
Devolatilization Step
[0064] A devolatilization step may be carried out after the metal
salt production step. As a result, unreacted bis (fluorosulfonyl)
imide and gases by-produced by the reaction can be removed. The
devolatilization step is preferably carried out at a temperature
not lower than the melting point of the bis (fluorosulfonyl) imide
metal salt. In the case of lithium bis (fluorosulfonyl) imide, the
devolatilization temperature is preferably not less than
143.degree. C. and not more than 160.degree. C. When the
devolatilization is performed at a temperature of lower than this
temperature range, the melt may solidify during devolatilization.
When the devolatilization is performed at a temperature of higher
than this temperature range, decomposition may occur. A pressure
range of the devolatilization may be changed according to the
devolatilization progresses, and the final pressure is not higher
than 50 kPa, preferably not higher than 10 kPa, more preferably not
higher than 5 kPa. In order to promote the devolatilization, an
inert gas such as nitrogen may be introduced into the solution.
However, the inert gas may not be introduced.
Shaping Step
[0065] In the shaping step, the shaped material of the bis
(fluorosulfonyl) imide metal salt is produced from the bis
(fluorosulfonyl) imide metal salt in molten state. As the bis
(fluorosulfonyl) imide metal salt in molten state, the bis
(fluorosulfonyl) imide metal salt obtained in molten state in the
production process can be directly used. The bis (fluorosulfonyl)
imide metal salt obtained as powder or the like can be also used by
heating and melting to be in molten state. As shaping methods, any
method can be used as long as it is solidified from the molten
state, and dry processes and wet processes can be exemplified.
[0066] As the dry processes, the following molding methods or the
like are exemplified. [0067] A drum flake granulation method in
which a molten liquid is applied to a rotating drum surface, cooled
and solidified to be shaped into a flake shape [0068] A casting
method in which a molten liquid is poured into a mold, cooled and
solidified to be shaped into a shape of the mold [0069] A roll-drop
steel belt granulation method in which, for example, a small amount
of molten liquid is scooped with comb teeth of a rotating drum,
dropped on a surface of a horizontally moving metal belt, cooled
and solidified to be shaped into a hemispherical shape, and then, a
solidified pellet is peeled off from the belt and collected by
passing through a scraper arranged on the other end of the belt
[Roll-Drop Type-Steel Belt Granulator manufactured by Nippon
Berding Co., Ltd., as an example] [0070] A rotoform steel belt
granulation method in which a molten liquid is extruded uniformly
from a hole of rotating outer shell on a surface of a horizontally
moving metal belt, cooled and solidified to be shaped into a
hemispherical shape, and then, a solidified pellet is peeled off
from the belt and collected by passing it through a scraper
arranged on the other end of the belt or by using the curvature of
the belt [Rotoform Granulation Systems manufactured by Sandvik K.
K.] [0071] A droplet dropping granulation method in which a molten
liquid is broken up with a vibrator little by little into a
droplet, and the droplet is naturally dropped, cooled and
solidified in cooling nitrogen vaporized liquid nitrogen or in
cooled and dried air to shape a spherical droplet
[Microsphere/Capsule Production Unit manufactured by BRACE GmbH, as
an example] [0072] A prilling tower granulation method in which a
molten liquid is sprayed from a nozzle and finely dispersed in a
mist form, solidified by cooling in contact with cool wind upon
falling down to shape into a spherical shape having a particle
diameter of 0.1 mm to 3 mm [0073] A screw extrusion-type
granulation method in which a flowing or semi-flowing molten liquid
is extruded from a screen die by screw, solidified by cooling, cut,
and shape into a spherical shape, or a hemispherical shape [0074] A
method in which a molten liquid is extruded into a plate shape, a
block shape, a rod shape or the like, solidified by cooling, and
then pulverized with a pulverizer to obtain a pulverized material
[0075] A melt crystallization method Some of the above methods may
be combined.
[0076] Examples of the wet processes include solvent
crystallization, recrystallization, concentration and
solidification, a method of extruding the melt into a poor solvent,
cooling and solidifying, and the like.
[0077] Among them, the rotoform steel belt granulation method and
the roll-drop steel belt granulation method are one of preferable
granulation methods because of little metal-to-metal contact
structurally and little contamination. Among them, the rotoform
steel belt granulation method is preferable. In the pellet produced
in the rotoform steel belt granulation method, a preferable size of
the pellet as a hemispherical diameter is more preferably not less
than 0.5 mm, further preferably not less than 1 mm, and
particularly preferably not less than 3 mm. Although an upper limit
is not particularly limited, and for example, it is preferably not
more than 50 mm, more preferably not more than 20 mm, and further
preferably not more than 10 mm.
[0078] By setting the particle diameter in this manner, the salt
can hardly absorb moisture, can hardly be scattered, and then, can
be easily handled. On the other hand, when the particle diameter is
more than the upper limit, the handling property becomes worse and
the dissolution rate into the electrolyte solvent becomes low.
[0079] Further, the method in which the molten liquid is extruded
into the plate shape, the block shape, the rod shape or the like,
solidified by cooling, and then pulverized with a pulverizer to
obtain a pulverized material is also one of a preferable embodiment
because the shaped material can be produced under conditions of
relatively high flexibility.
[0080] In the present invention, the method for preparing the bis
(fluorosulfonyl) imide metal salt may comprise a grinding step of
grinding the shaped material obtained in the shaping step.
Cooling Step
[0081] The shaping step preferably includes a cooling step after
melting the bis (fluorosulfonyl) imide metal salt. The cooling
temperature in the cooling step is not limited as long as the
melting bis (fluorosulfonyl) imide metal salt can be solidified.
The cooling temperature is preferably not less than a room
temperature, more preferably not less than 40.degree. C., and
further preferably 50 to 60.degree. C. An upper limit is preferably
not more than 140.degree. C., more preferably not more than
100.degree. C., further preferably not more than 80.degree. C.,
particularly preferably less than 80.degree. C.
[0082] The cooling temperature may be constant, or it may be
changed stepwise. When changing stepwise, as an example, a crystal
nucleus generation step and a crystal growth step are included, and
the temperature is set suitable for each step. A cooling
temperature in the crystal nucleus generation step is preferably
not less than 0.degree. C., more preferably not less than
20.degree. C., further preferably not less than 30.degree. C. It is
preferably not more than 90.degree. C., more preferably not more
than 70.degree. C., further preferably not more than 50.degree. C.
A cooling temperature in the crystal growth step is preferably not
less than 30.degree. C., more preferably not less than 40.degree.
C., and further preferably not less than 50.degree. C. It is
preferably not more than 110.degree. C., more preferably not more
than 90.degree. C., further preferably not more than 70.degree. C.,
particularly preferably not more than 60.degree. C.
[0083] In the cooling step, seed crystals are preferably used.
[0084] By contacting with a small amount of crystals (seed
crystals) during solidification by cooling, the crystal growth time
can sometimes be shortened. In this case, in a method of contacting
with the small amount of crystals, the crystals may be attached to
a belt or a metal mold beforehand, or a slight residue left behind
after removing the product solidified previously may be used as in
the case of solidifying by cooling on the rotating drum or the
rotating belt.
[0085] The production of the shaped material of bis
(fluorosulfonyl) imide metal salt may be carried out under reduced
pressure, or may be carried out while supplying gases to a shaped
material manufacturing apparatus. Examples of usable gases include
inert gases such as nitrogen and argon, and dry air.
[0086] The production of the shaped material of bis
(fluorosulfonyl) imide metal salt is preferably carried out in an
environment having a dew point of -25.degree. C. in order to
prevent moisture absorption. More preferably not more than
-30.degree. C., further preferably not more than a dew point of
-40.degree. C., particularly preferably not more than a dew point
of -50.degree. C., more preferably not more than -60.degree. C.
[0087] The raw materials such as bis (chlorosulfonyl) imide,
hydrogen fluoride, and the alkali metal compound, preferably used
in the above-mentioned steps, can be purified with known methods
such as distillation, crystallization and reprecipitation after
dissolve in solvents if necessary.
[0088] Preferably, the bis (chlorosulfonyl) imide, the hydrogen
fluoride and the alkali metal compound used as raw materials; the
bis (fluorosulfonyl) imide and the bis (fluorosulfonyl) imide
alkali metal salt as products; and hydrogen chloride, hydrogen
fluoride, and the like which may be generated as by-products can be
recovered by known methods such as distillation, crystallization
and reprecipitation after dissolving in solvents if necessary.
4. Non-Aqueous Electrolytic Solution
[0089] The bis (fluorosulfonyl) imide metal salt of the present
invention [particularly, lithium bis (fluorosulfonyl) imide] is
suitably used as a non-aqueous electrolytic solution used in, for
example, an electric double layer capacitor, a lithium ion cell and
a lithium ion capacitor. A content of the bis (fluorosulfonyl)
imide metal salt in the electrolytic solution is preferably more
than 0.5 mol/L and not more than 6.0 mol/L, more preferably not
less than 0.6 mol/L and not more than 4.0 mol/L, further preferably
not less than 0.6 mol/L and not more than 2.0 mol/L, and most
preferably not less than 0.6 mol/L and not more than 1.5 mol/L. By
setting the content of the bis (fluorosulfonyl) imide metal salt in
the electrolytic solution to such a range, cell performance can be
improved.
[0090] The electrolytic solution may contain other known
components. Examples of the other components include the other
lithium salts such as LiPF.sub.6, radical scavengers such as
antioxidants and flame retardants, and redox type stabilizers.
[0091] Solvents which can be used for the electrolytic solution are
not particularly limited as long as they can dissolve and disperse
electrolytic salts (for example, the sulfonylimide compounds and
the above-mentioned lithium salts). Examples of the solvents
include non-aqueous solvents such as cyclic carbonates and chain
carbonates, and media such as polymers and polymer gels used in
place of solvents. As the solvents, any of the conventionally known
solvents used in cells can be used.
5. Antistatic Agent
[0092] The bis (fluorosulfonyl) imide metal salt of the present
invention [particularly, lithium bis (fluorosulfonyl) imide] is
also suitably used as antistatic agent for imparting antistatic
performance to polymeric materials.
[0093] Examples of the polymer materials include thermoplastic
resins, thermosetting resins, rubber and the like.
[0094] Examples of the thermoplastic resins include polyolefin
resins such as polyethylene, polypropylene and polystyrene, and
compositions thereof; polyacetal, polyacrylate, acrylic resin and
compositions thereof; polyphenylene ether type resins such as
polyphenylene ether (PPE), PPE/polystyrene, PPE/polyamide (PA) and
PPE/polybutylene terephthalate (PBT), and compositions thereof;
polyester type resins such as polyether ketone, polyethylene
terephthalate (PET) and PBT/ABS, and compositions thereof;
polycarbonate resins such as polycarbonate (PC), PC/ABS, PC/PET and
PC/PBT, and compositions thereof; polyurethane and its composition;
polyvinyl chloride, polyvinylidene chloride; polyimide,
polyetherimide, polyamideimide; polyphenylene sulfide type resin
and its composition; polysulfone, and the like. It is preferable to
use one or more of these. Among them, acrylic resins, polyester
resins, polyamide resins, polyurethane resins, polyvinyl chloride
resins, and epoxy resins are more preferable on the viewpoint of
excellent conductivity, and it is preferable to use at least one
kind of these resins as the polymer materials.
[0095] Examples of the thermosetting resins include phenol resins,
urea resins, melamine resins, alkyd resins, unsaturated polyester
resins, epoxy resins, silicon resins, polyurethane resins and the
like, and one or more of these can be used preferably.
[0096] Examples of the rubber include urethane rubber, acrylic
rubber, acrylonitrile-butadiene rubber, epichlorohydrin rubber,
epichlorohydrin-ethylene oxide copolymer rubber, silicone rubber,
fluoro olefin vinyl ether copolymer urethane rubber, styrene
butadiene copolymer rubber and their foams and the like, and it is
preferable to use one or more of them.
[0097] An amount of blending antistatic agent may be appropriately
determined depending on the application, and it is preferably, for
example, not less than 0.1 parts by mass and not more than 50 parts
by mass to 100 parts by mass of the above polymer materials. More
preferably not less than 1 part by mass, further preferably not
less than 5 parts by mass, more preferably not more than 20 parts
by mass, further preferably not more than 10 parts by mass. When
the amount of blending antistatic agent is too large, the
antistatic agent may bleed. On the other hand, when the amount of
blending antistatic agent is too small, it may be difficult to
obtain desired antistatic performance.
[0098] The antistatic agent using the bis (fluorosulfonyl) imide
metal salt of the present invention can be suitably used as
antistatic agents used in, for example, conductive sheets; PCT
(Pressure Cooker Test) elements; charging members in
electrophotographic printers, copying machines or the like,
cleaning members, developing members, transfer members; various
formed bodies such as polymer temperature sensitive materials,
household appliances/office automation equipment, housing products
such as game machines and office equipment and the like, various
plastic containers such as IC (integrated circuit) trays, films for
various packaging materials, sheets for flooring materials,
artificial turf, mats, and automobile parts; resin materials having
antistatic properties.
EXAMPLES
[0099] Hereinafter, the present invention will be described in more
detail with reference to examples, but the present invention is
originally not limited by the following examples, and appropriate
modifications are of course also possible to make within a range
that can conform to the gist of the foregoing and the following to
implement the invention, and all of them are included in the
technical scope of the present invention.
Measurement of Average Particle Diameter
[0100] 50 g of formed bodies of LiFSI [lithium bis (fluorosulfonyl)
imide] was put into a standard JIS sieve according to JIS Z 8801-1,
and the sieve was covered with an upper lid and a bottom lid. After
shaking the sieve up and down 300 times, a particle diameter
distribution was measured and the 50% average particle diameter was
calculated. When there were particles bigger than the mesh size not
defined in JIS Z 8801, the 50% average particle diameter was
defined by actually measuring with a calliper and setting a minimum
length as the particle diameter instead.
Measurement of Loose Bulk Specific Gravity
[0101] The loose bulk specific gravity (d) was obtained by the
following formula according to the Japan Powder Industry Technology
Association standard SAP 05-98.
d=x/y(g/cm.sup.3)
In the above formula, y cm.sup.3 was a volume of x g of sample when
the x g of sample was naturally fell into a 100 cm.sup.3 measuring
cylinder from a funnel with a height of 10 cm.
Measurement of Amount of Residual Solvent: Headspace Gas
Chromatography Analysis Method
[0102] 200 .mu.l of dimethylsulfoxide aqueous solution
(dimethylsulfoxide/ultrapure water=20/80, volume ratio), and 2 ml
of 20 mass % sodium chloride aqueous solution were added to 0.05 g
of the LiFSI composition obtained in the following examples to make
a measurement solution. The measurement solution was placed in a
vial bottle, hermetically sealed, and measured an amount of
residual solvent contained in fluorosulfonylimide alkali metal salt
with headspace-gas chromatography system ("Agilent 6890",
manufactured by Agilent Technologies, Inc.).
[0103] Apparatus: Agilent 6890
[0104] Column: HP-5 (length: 30 m, column inner diameter: 0.32 mm,
film thickness: 0.25 .mu.m) (manufactured by Agilent Technologies,
Inc.)
[0105] Column temperature condition: 60.degree. C. (held for 2
minutes), heating up to 300.degree. C. by 30.degree. C./minute,
300.degree. C. (held for 2 minutes)
[0106] Head space condition: 80.degree. C. (held for 30
minutes)
[0107] Injector temperature: 250.degree. C.
[0108] Detector: FID (300.degree. C.)
Example 1
[0109] 11.70 g (0.45 mol) of LiF was weighed out and put into a PFA
reaction vessel. The reaction vessel was cooled with ice, and 95.9
g (0.53 mol) of HFSI [bis (fluorosulfonyl) imide] was added. The
solution for reaction was heated to 120.degree. C. and reacted for
1.5 hours. The reacted solution was dried under reduced pressure
for 2 hours at 10 hPa at 140.degree. C. to 145.degree. C. As a
result, 73 g of LiFSI was obtained (in molten state).
[0110] The obtained LiFSI was sucked with a dropper while
maintaining its temperature at 140.degree. C. to 145.degree. C.,
quickly fell down as a droplet on a plate made of SUS 304 heated to
60.degree. C. and solidified to obtain pellets. The mass average
particle diameter of the pellets after solidification was 4.8 mm.
The water content was 54 mass ppm. In addition, the amount of
residual solvent was below the detection limit (not more than 1
mass ppm). The loose bulk specific gravity of the obtained pellets
was 1.12. The above reaction and operation were carried out in a
dry room having a dew point of not more than -50.degree. C.
Example 2
[0111] 905 g (5.00 mol) of HFSI [bis (fluorosulfonyl) imide] and
132 g (5.10 mol) of LiF were put into a stainless reaction vessel
equipped with a nitrogen introduction tube and a reflux tube. The
solution for reaction was heated to 150.degree. C. with stirring.
Thereafter, the inside pressure of the reaction vessel was reduced,
and the reaction solution was heated at 10 hPa and 145.degree. C.
to 150.degree. C. for 2 hours. As a result, 890 g (4.76 mol) of
LiFSI was obtained (in molten state).
[0112] The obtained reacted solution was transferred with adding
pressure through a heating pipe to a connected steel belt type
granulating apparatus (Rotoform M1) manufactured by Sandvik K. K.
The molten liquid was extruded on the steel belt at 160.degree. C.
with an outer shell (opening diameter: 2 mm.PHI.) of a granulating
section. The extruded molten liquid was scrapped off with a
scraper, and the scrapped material was not collected until the
steel belt took to complete one revolution. The pellets were
collected after the belt taken to complete one revolution. At this
time, the crystal nucleus generation time was set to 1 minute and
the crystal growth time was set to 2 minutes, and the belt
temperature in each was set to 25.degree. C. and 60.degree. C.
[0113] The obtained pellets had the hemispherical shape and had the
mass average diameter of 5.7 mm.PHI.. The water content was 17 mass
ppm. In addition, the amount of residual solvent was below the
detection limit. The loose bulk specific gravity of the obtained
pellets was 1.24. The above reaction and operation were carried out
in a dry room having a dew point of not more than -50.degree.
C.
Example 3
[0114] 905 g (5.00 mol) of HFSI [bis (fluorosulfonyl) imide] and
129 g (4.98 mol) of LiF were put into a stainless reaction vessel
equipped with a nitrogen introduction tube and a reflux tube. The
solution for reaction was heated to 150.degree. C. with stirring,
and reacted for 1.5 hours. Thereafter, the reaction solution was
heated at 10 hPa and 145 to 150.degree. C. for 2 hours. As a
result, 890 g (4.76 mol) of LiFSI was obtained (in molten
state).
[0115] A pipe for pulling out products was connected to this
reaction vessel, and the LiFSI molten liquid was pulled out by
pressurizing through a nitrogen introduction pipe. The molten
liquid was pulled out to a mold having a depth of 1 cm, a width of
1.75 cm, and a length of 2 cm, and the mold was cooled at
50.degree. C. to obtain a block-shaped material of LiFSI. By
measuring the obtained shaped material of LiFSI with a caliper, the
minimum length was 10 mm. In addition, the water content was 7 mass
ppm. The amount of residual solvent was below the detection limit.
The above reaction and operation were carried out in a dry room
having a dew point of -50.degree. C. or less.
Example 4
[0116] 11.70 g (0.45 mol) of LiF was weighed out and put into a PFA
reaction vessel. The reaction vessel was cooled with ice, and 95.9
g (0.53 mol) of HFSI [bis (fluorosulfonyl) imide] was added. The
solution for reaction was heated to 145.degree. C. Thereafter, the
inside pressure of the reaction vessel was reduced, and the
reaction solution heated at 10 hPa and 145.degree. C. to
150.degree. C. for 2 hours. As a result, 73 g of LiFSI was obtained
(in molten state).
[0117] The obtained LiFSI was sucked with a dropper while
maintaining in molten state, quickly fell down as a droplet on a
plate made of SUS 304 heated to 60.degree. C. and solidified to
obtain pellets. The mass average particle diameter of the pellets
after solidification was 5.4 mm. The water content was 10 mass ppm.
The loose bulk specific gravity of the obtained pellets was 1.10.
The above reaction and operation were carried out in a dry room
having a dew point of not more than -50.degree. C.
Comparative Example 1
[0118] 1800 g of butyl acetate was added to a Pyrex (registered
trademark) reaction vessel A (internal capacity 10 L) equipped with
a stirrer under nitrogen stream, and 200 g (934 mmol) of bis
(chlorosulfonyl) imide was added dropwise at room temperature
(25.degree. C.).
[0119] 101 g [982 mmol, 1.05 equivalents based on bis
(chlorosulfonyl) imide] of zinc fluoride was added all at once at
room temperature to the obtained butyl acetate solution of bis
(chlorosulfonyl) imide, and stirred at room temperature for 6 hours
to be completely dissolved.
[0120] 540 g (7928 mmol, 8.49 equivalents based on bis
(chlorosulfonyl) imide) of 25 mass % aqueous ammonia was added to
Pyrex (registered trademark) reaction vessel B (internal capacity
10 L). The solution for reaction in the reaction vessel A was added
dropwise to the reaction vessel B at room temperature under
stirring ammonia water. After completion of the dropwise addition
of the solution for reaction, stirring was stopped. From the
reacted solution divided into two layers of an aqueous layer and a
butyl acetate layer, the aqueous layer containing by-products such
as zinc chloride was removed to obtain ammonium bis
(fluorosulfonyl) imide of butyl acetate solution as an organic
layer. .sup.19F-NMR (solvent: trideuteroacetonitrile) measurement
was carried out on the obtained organic layer as a sample. In the
obtained chart, the crude yield of the ammonium bis
(fluorosulfonyl) imide contained in the organic layer was
determined (756 mmol) from the amount of trifluoromethylbenzene
added as an internal standard substance and the comparison of the
integrated value of the peak derived from trifluoromethylbenzene
with that derived from the target product.
[0121] .sup.19F-NMR (solvent: trideuteroacetonitrile): .delta.
56.0
[0122] 242 g of 15 mass % lithium hydroxide aqueous solution (1516
mmol as Li) was added to the ammonium bis (fluorosulfonyl) imide
contained in the obtained organic layer such that the amount of
lithium was 2 equivalents based on the ammonium bis
(fluorosulfonyl) imide. The resulting mixture was stirred at room
temperature for 10 minutes. Thereafter, aqueous layer was removed
from the reacted solution to obtain a butyl acetate solution of
lithium bis (fluorosulfonyl) imide. The obtained organic layer was
used as a sample for analysis, it was confirmed by the ICP emission
spectroscopic analysis that ammonium cations of fluorosulfonylimide
were exchanged for lithium ions. The concentration of lithium bis
(fluorosulfonyl) imide in the organic layer was 7 mass % (yield:
127 g, 73%).
[0123] The concentration of fluorosulfonylimide was determined from
the amount of trifluoromethylbenzene added as an internal standard
substance and the comparison of an integrated value of the peak
derived from trifluoromethylbenzene with that derived from the
target product, in the chart of the measurement results of
.sup.19F-NMR (solvent: trideuteroacetonitrile) measurement about
the obtained organic layer as a sample.
[0124] The lithium bis (fluorosulfonyl) imide solution obtained by
cation exchange was added to a rotary evaporator ("REN-1000",
manufactured by IWAKI Corporation) and the solvent was distilled
off under reduced pressure to obtain 282 g of a lithium bis
(fluorosulfonyl) imide solution (concentration: 45 mass %).
[0125] Then, a flask (capacity: 500 mL) containing 200 g of the
butyl acetate solution of lithium bis (fluorosulfonyl) imide having
a concentration of 45 mass % was attached in a rotary evaporator
("REN-1000", manufactured by IWAKI Corporation). While blowing
nitrogen gas into the liquid in the flask at a rate of 500 mL/min,
rotation was started (100 rpm) while heating in a constant
temperature water bath set at 60.degree. C. Subsequently, the
interior of the apparatus was gradually depressurized to 933 Pa,
and a concentrating step was performed for 12 hours. The
concentration of the obtained solution was 72 mass %. The amount of
heat added in the concentrating step was 72,000 J per 1 g of
lithium bis (fluorosulfonyl) imide.
[0126] 125 g of toluene was added to 125 g of the obtained
concentrated solution, and the mixture was allowed to stand at
25.degree. C. for 1 hour to precipitate a solid of lithium bis
(fluorosulfonyl) imide. The obtained solid was collected by
filtration and vacuum dried at 50.degree. C. to obtain powdered
lithium bis (fluorosulfonyl) imide (LiFSI) [yield: 68 g, 76% (from
concentrating step)]. The mass average particle diameter of
obtained LiFSI was 50 .mu.m. The water content was 52 mass ppm. In
addition, the amount of residual solvent was 980 mass ppm. The
loose bulk specific gravity of the obtained powder was 1.34.
Measurement of Moisture Absorption Rate
[0127] 7 g of LiFSI obtained in each of Examples 1 to 3 and
Comparative Example 1 was precisely weighed and put in a
polyethylene bag having a thickness of 80 .mu.m and a size of 50
mm.times.70 mm (trade name: Unipac Model No. A-8, manufactured by
SEISANNIPPONSHA LTD.). Then, a chuck portion was sealed by welding
with a heat sealer.
[0128] It was left under the condition of 23.degree. C. and 65%
humidity, and the mass changes after 30 minutes and 90 minutes were
weighed with a precision balance. The average moisture absorption
rates for 30 minutes are shown in Table 1.
TABLE-US-00001 TABLE 1 Comparative Example 1 Example 2 Example 3
Example 4 Example 1 mass ppm/ mass ppm/ mass ppm/ mass ppm/ mass
ppm/ minute cm.sup.2 min cm.sup.2 min cm.sup.2 min cm.sup.2 min
cm.sup.2 min 0 0.00 0.00 0.00 0.00 0.00 30 0.00 0.00 0.00 0.00 2.77
90 0.00 0.00 0.00 0.00 1.43
[0129] As described in Examples 1 to 4, it was found that the bis
(fluorosulfonyl) imide metal salts having an average particle
diameter of not less than 0.1 mm were more difficult for moisture
absorption and scattering, and easier for handling than that
obtained in the Comparative Example 1.
INDUSTRIAL APPLICABILITY
[0130] In the present invention, the bis (fluorosulfonyl) imide
metal salt and the method for preparing the bis (fluorosulfonyl)
imide metal salt can be applied in various uses such as additives
to electrolytes or fuel cell electrolytes, selective electrophilic
fluorinating agents, photo acid generators, thermal acid
generators, and near infrared absorbing dyes.
* * * * *